The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Clock synchronization protocols are commonly used in packet-based networks to synchronize clocks maintained at different network devices. In such clock synchronization protocols, a first network device, which maintains a master clock, transmits a protocol message including a master clock time to a second network device, which maintains a slave clock. The second network device utilizes the master clock time and an estimated network latency to adjust the slave clock in order to synchronize the slave clock with the master clock.
Additionally, such clock synchronization protocols are exposed to security threats. For example, in a so-called delay attack, a malicious man-in-the-middle adversary selectively adds delay to clock synchronization time-stamped packets sent between the master clock and the slave clock. The delay attack prevents the second network device discussed above from correctly measuring the network latency, and thus proper synchronization between the slave clock and the master clock is frustrated.